Electric train signaling apparatus



Jan. 3, 1933. R. P. BAL LOU 1,392,716

ELECTRIC TRAIN SIGNALING APPARATUS Filed Jan. 28, 1932 Cap 006401017 if 9 5 1 20001001 I-ii-i-il 1 5 5 I T I r i-n mmsmzzzep Fig. 2.

IN VENTOR. Hl'OhaPd RBallou.

HIS ATTORNEY.

Patented Jan. 3, 1933 UNITED-STATES PATENT OFFICE RICHARD P. BALLOU, 'OF 'WILKINSB'URG, PENNSYLVANIA, ASSIGN'OR- TO THE UNION SWITCH 6t SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CQETPORATION GIE PENNSYLVANIA ELECTRIC TRAIN SIGNALING APPARATUS Application filed January 28, 1932. Serial No. 589,398.

My invention relates to electric train signaling apparatus of the type disclosed and claimed in application for Letters Patent of the United States filed by L. O. Grondahl, on May 6, 1930, Serial No. 450,135, for electric train signaling systems. One feature of my invention is the arrangement of the apparatus shown in the aforesaid application in such manner that the apparatus will provide maximum efficiency for both the sending and the receiving of current impulses and will be substantially immune to false disturbances created by foreign space magnetic fields.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. l' is a diagrammatic view showing one'arrangement of apparatus embodying my invention. Fig. 2 is a diagrammatic view showing a second form of apparatus that also embodies my invention. In the two views like reference characters designate corresponding parts.

Referring to Fig. l, the reference characters 1 and 1 designate the traflic rails of a railway track, and the reference character 2 designates the coupler of a train traveling on said track. The rest of the apparatus is mounted on the train. The train-carried apparatus includes two inductors designated by the reference characters 3 and 3* located above the two traffic rails 1 and 1", respectively, and a third inductor 4 located beneath the train coupler 2. Inductors 3 and 3 preferably but not necessarily have magne tizable cores 21 and 22 on which are wound windings 5 and 5*, respectively. Inductor l is also preferably provided with a magnetizable core 23 on which is wound a winding 6 provided with a tap 7. To aid in the understanding of my invention I shall, in the following description, refer to windings 5 and 5 as consisting of one hundred turns each and winding 6 as having two hundred turns with one hundred turns each side of the tap 7, but which is not necessarily a center tap. It will be considered also that all the windings are constructed in a similar manner and th at the cores 21, 22 and 23 have like dimensions. It will be understood, how Yer, that my invention is in no way limited to inductors having windings of any specific number of turns or of any specific dimensions but those mentioned above are selected only for the purpose of aiding in the understanding of the operation of the apparatus.

The windings of the three inductors are adapted to be connected in series with the transmitter T or electromagnetic receiver R. The transmitter T and the receiver R may be any one of many well-known types among them being the vacuum tube type of a generator of alternating current for the transmitter and a telephone receiving set for the receiver. As the specific type of neither the transmitter T nor the receiver It forms a part of my invention, these devices are indicated by symbols only in order to simplify the drawings as much as possible. With the circuit controller K in its normal position as shown by the solid lines in Fig. l a circuit is comp eted from the top terminal of the receiver R along wire 8. contact 9 of circuit controller K, w1re 10, full two hundred turns of winding- 6, wire 11, winding 5, wire 12,

winding 5, wire 13, contact 14 and wire 15 to the lower terminal of the receiver R. The depressing of the circuit controller K to its dotted line position opens the abovetraced circuit to the receiver R- at the contacts 9 and 14 and completes a circuit from one term nal of transmitter T through wire 16, contact 17 of circuit controller K. wire 18, tan 7. and one hundred turns of winding 6, wire 11, winding 5, wire 12, winding 5*, wire 13. contact 19 and wire 20 to the other terminal of the transmitter T. It follows that when the circuit to the receiver R is closed the winding 6 has twice as many turns as either winding 5 or 5* and when the circuit to the transmitter T is closed windings 6, 5, and 5 each consist of an equal number of turns.

In connection with the previously mentioned Grond'ahl application, it has been found that under certain conditions the mostefle'ctive transmitting condition is obta ned when the windings impress substantially equal eect'romotive forces, on each of the two trailic rails and on the coupler.

With windings 5, 5 and 6 each provided with an equal number of turns during the sending period and the inductors 3, 3, and at spaced an equal distance from the tratlic rails and the coupler, substantially equal electromotive forces will be induced in each rail and in the coupler by the apparatus of Fig. 1. That is to say, the most effective transmitting; conditions for the previously mentioned Grondahl train signaling system is obtained by the apparatus of my invention as shown in Fig. 1.

It is apparent that the induction established in the coupler 2 can be made equal to that established in each trafiic rail even though winding 6 be made to include its full two hundred turns in place of one hundred turns mentioned above by spacing the inductor 4 at some greater distance away from the coupler 2. The mutual inductance of the three inductors is very low and thus practically all the impedance of any one of the inductors is due to its own reactance as the ohmic resistance of the winding will be small. The reactance of a winding increases as the square of the number of turns and hence if the windings of the track inductors 3 and 3 each have one hundred turns and the winding 6 of inductor 41 be made two hundred turns the total overall reactance oi the three inductors in series can be expressed as being equal to 1 plus 1 plus 4 equals 6 arbitrarily chosen inductance units. It winding 6 of inductor l be made one hundred turns the same as windings 5 and 5 the overall reactance of the three inductors in series can be expressed as being equal to 1 plus 1 plus 1 equals 3 arbitrarily chosen inductance units. Any given transmitter will, therefore, supply approximately the square root of two 5) times as much current to the circuit when each winding consists of one hundred turns each as it will supply when the winding 6 is made two hundred turns and windings 5 and 5 one hundred turns each. The induction created by an inductor is directly proportional to the ampere turns and thus it follows that approximately forty per centmore voltage will be induced in each trafiic rail and in the coupler when the windings ot the inductors are each made one hundred turns than will be obtained when windings 5 and 5 each consists of one hundred turns and the winding 6 of two hundred turns. It is to be seen, therefore, that any given transmitter will create maximum induction when the overall inductance of the three inductors is a minimum, the number of turns on the desirable to reduce the number of turns on the coupler inductor as much as possible, maintaining the same induced voltage by decreasing as much as possible the distance between the coupler and its inductor. In Fig. 1 this condition is illustrat d with one hundred turns on the coupler inductor.

When the inductors 3, 3, and 4 are connected to the receiver R for the purpose of picking up energy from the traffic rails and the train coupler, the windings are connected in series in a manner to add their inductive effeetwhen the current flows in the traffic rails and in the coupler in the same direction at any given instant. It has been found that foreign space magnetic fields may create an induction in the windings of the train-carried inductors and thereby create false disturbances in the receiving device. As the train carried inductors are symmetrically arranged transverse to the track the influence of any space magnetic field may be considered as having a direction transverse to the traflic track as indicated by the arrows shown atthe left-hand end of Fig. 1. The connection of winding 6 in the receiving circuit is such that inherently the voltage induced therein by a space magnetic field opposes the voltage induced by the same field in the windings 5 and 5. \Vith winding 6 made two hundred turns then its induced voltage by the external field will balance out the combined voltages induced in the two windings 5 and 5' of one hundred turns each by the same field. As previously pointed out with the circuit controller K in its normal position to connect the inductors to the receiver R the winding 6 is made to consist of two hundred turns and thus the apparatus of Fig. 1 is so proportioned as to substantially balance out the influence of a foreign space magnetic field on the receiver R.

To sum up the operation of the apparatus of Fig. 1, when the circuit controller K is depressed to establish. the sending condition, the apparatus is so proportioned that the opt mum relation for maximum induction and the most effective transmitting condition is obtained. hen the circuit controller K is set to establish the receiving condition, the apparatus is so proportioned as to be substantially insensitive to any external magnetic fields that might create false disturbances in the receiving device.

The apparatus of 1, having but a single given condition when connected to receiver R. is immune to external fields only when said fields are uniform in intensity throughout the space occupied by the trainarried inductors. It has been found that foreign space magnetic fields not always uniform throughout the range of the traincarried apparatus. At locations of underground crossings of power supply lines and feeder systems for electric railways the space 1 receiving circuit.

magnetic fieldin the range of the train-carried apparatus may be far from uniform. Under these circumstances more or less turns may be added to the winding of the coupler inductorto obtain the optimum balancing out of the voltage induced in the track inductors by the space magnetic field.

In Fig. 2, the winding 6 of inductor 4 is made of one hundred turns equal to the windings 5 and 5 of the track inductors. As de scribed above, this arrangement, although desirable for transmitting, not one that will obtain a balance of the effect created by a foreign space magnetic field when receiving. I In the form of the apparatus of Fig. 2, a coupling inductor 24 is added to the apparatus. The inductor 24 is provided with two windings 25 and 26 wound in opposite directions. The winding 25 has a series of taps brought out at different points on the winding to different contacts as will be readily understood by an inspection of Fig. 2. In a like manner the winding 26 has several taps brought out at different points and each connected to-a different contact. The manually operated circuit controlling contact member 27, pivoted at O, is adapted to engage successively the contacts associated with the taps of winding 26 when it is moved to the right from its center position and to engage the contacts associated with the taps of winding 25 when moved to the left. The inductor 24 is preferably located near the re ceiver but not shielded and is in such a posi tion that it will be inductively influenced by a space magnetic field. Preferably the inductor 24 will be so constructed as to have a power factor substantially equal to the power factor of the totality of the threeinductors 3, 3 and 4. With the contact member 27 occupying its center position, as shown in Fig. 2, a circuit is formed for the receiver R that can be traced from the top terminal of B through contact 28 of the circuit controller K, windings 6, 5, and 5 of inductors 4, 3, and 3 respectively, contact 29 of circuit controller K, wire 30, contact member 27, and to the lower terminal of the receiver R. WVith contact member 27 swung to the left, a greater or lessnumber of turns of winding 25 are included in the circuit to the receiver R while when contact member 27 is swung to the right, a greater or less number of turns of winding 26 are included in the As stated above, windings 25 and 26 are wound in opposite directions. Assuming the winding 25 to be of a direction such that it adds its inductive effect created therein by a space magnetic field to that of i the winding 6 created by the same field, then the winding 26 will subtract its inductive effect created by a space magnetic field from that created by the same field in the winding 6. As stated hereinbefore the position and connection of winding 6 are such that volt ages induced therein by space magnetic fields oppose the'voltage induced in the windings 5 and 5. It follows that by manipulating contact member 27 to the right or to the left, a condition can be readily reached where the voltage induced in the winding 6 plus or minus the voltage induced in the windings 25 or 26 will be equal and opposite to the sum of the voltages induced in the windings 5 and 5 by the same external field whether or not the external field is uniform in intensity throughout the range of the train carried apparatus- It is evident, therefore, that by such an arrangement of apparatus as shown in Fig. 2 any foreign disturbance uponthe receiver R can readily be eliminated.

lVhile in Fig. 2 the coupling inductor24 is disclosed as consisting of windings whose number of turns can be varied, it will be understood that it can equally as well be a single coil adapted to be rotated in any one of two or three dimensions. Such a coil can readily'be set in a position so that its effect when combined with that of the windingv 6 will balance out the effect created upon the windings 5 and 5 by any space magnetic field. Again a number of different taps may be provided for the winding 6 similar to the tap 7 of Fig. 1 and the different taps connected to contacts. By a contact member similar to the contact member 27 the number of effective turns for the winding 6 could be selected un der the receiving condition that will produce a balance for the effect of space magnetic fields upon the inductors. As a matter of fact, the winding 6 may be eliminated during transmission, that is, made of zero number of turns, and then connected into circuit with any desired number of turns during receiving periods.

Apparatus such as here described when set to receive electromagnetic induction from the traflic track is insensitive to foreign magnetic fields and when set to transmit electromagnetic induction to the traffic track is so proportioned and positioned as to obtain maximum induction at the most effective distribution of the induction.

Although I have herein shown and described only certain forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: V

1. Train signaling apparatus of the type comprising three windings on a train disposed in inductive relation to the two track rails and a train coupler respectively and adapted to either receive or transmit by electromagnetic induction, said apparatus being characterized by the fact that the winding associated with the coupler has twice as many efi'ective turns as either of the other two windings during receiving and substantially the same number of effective turns as each of the other two windings during transmission.

2. Train signaling apparatus of the type comprising three windings on a train dis posed in inductive relation'to the two track rails and a train coupler respectively, a circuit controller adapter to connect said windings to either a source of current or to a receiving device, said apparatus being characterized by the fact that the effectiveness of the winding associated with the coupler is made equal to the combined effectiveness of the two coils associated with the rails when said windings are connected to the receiving device and is made equal to each of the other two windings when they are connected to the source of current.

3. Train signaling apparatus of the type comprising three windings on a train disposed in inductive relation to the two track rails and a train coupler respectively, a circuit controller adapted to connect said windings in series to either a source of current or to a receiving device, said apparatus being characterized by the fact that the windings are so proportioned when connected to the receiving device as to be substantially iminune to space magnetic fields and are so proportioned when connected to the source of current as to establish optimum induction in the coupler with maximum in the trailic rails.

4. Train signaling apparatus of the type comprising a plurality of train carried inductors adapted to either receive from or transmit to a tratfic track by electromagnetic induction, and means for establishing an arrangement of said inductors in a condition to be most effective in transmitting electromagnetic induction to the trafiic track and to vary the arrangement of said inductors to a condition to obtain maximum immunity from foreign space magnetic fields during the receiving of electromagnetic induction from the traific track.

5. Train signaling apparatus of the type comprising three windings on a train disposed in inductive relation to the trafiic rails and a train coupler respectively and adapted to either receive or transmit by electromagnetic induction and characterized by the fact that the number 01 turns of the two windings associated with the tralfic rails are equal while the number of effective turns of the winding associated with the coupler may be varied, and means to select the number of effective turns for the last mentioned winding and thereby cause the voltage induced in the coupler to be equal to that induced in each tralfic rail during the transmitting of electro magnetic induction and to cause the voltage 'iduced in the winding associated with the coupler by a changing magnetic field from an external source to be equal and opposite to the sum of the voltages induced by the same field in the other two windings during the receiving of electromagnetic induction.

6. Train signaling apparatus of the type comprising, three windings on a train one each disposed in inductive relation with the traliic rails and the third winding in an inductive relation with a train coupler, a circuit controller adapted to connect said windings to either a source of current or to a receiving device, said apparatus so proportioned as to establish equal induction in each trafiic rail and in the coupler when connected to the source of current and so connected together that the induction due to a space magnetic field in the winding associated with the coupler opposes the induction created by said field in the two windin associated with the trafiic rails, a fourth winding on the train inductively influenced by spaced magnetic fields, and means to vary the effectiveness of said fourth winding and to so combine its influence with that created by the space mag netic field in the winding associated with the coupler that maximum immunity for the apparatus from space magnetic fielcs is obtained.

7 Train signaling apparatus of the type comprising four windings on a train one each disposed in inductive relation with the traffic rails and one in an inductive relation with a train coupler and the fourth winding posi tioned to be influenced by space magnetic fields only, a circuit controller adapted to connect said windings either to a source of current or to a receiving device, said apparatus being characterized by the fact that the windings associated with the traffic rails and the coupler are so proportioned as to establish equal induction in each traffic rail and the coupler when the windings are connected to the source of current and the four windings so proportioned when connected to the receiving device that the combined induction of the coupler winding and the fourth mentioned winding by any space magnetic field substantially balances out the combined induction of the two windings associated with the traffic rail by the same field.

8. Train signaling apparatus of the type comprising three windings on a train one each disposed in inductive relation with each traffic rail and one winding disposed in inductive relation with a train coupler, a circuit Controller adapted to connect said windings to either a source of current or to a receiving device, said apparatus being characterized by the fact that the windings are so proportioned as to establish equal. induction in each trafiic rail and the coupler when connected to the source of current and the voltage induced in the winding associated with the coupler by a space magnetic field oppose the voltage induced in the windings associated with the trafic rails when connected to the receiving device, a fourth winding on the train adapted to be influenced by space magnetic fields, and means for varying the efi'ectiveness of said fourth winding and combining the voltage induced therein with that induced in the first mentioned three windings by a space magnetic field to balance out the efiect of the space field on the apparatus.

9. Train signaling apparatus of the type comprising three windings on a train one each disposed in inductive relation with each trafiic rail and one winding disposed in inductive relation with a train coupler, a circuit controller adapted to connect said windings to either a source of current or to a receiving device, said apparatus being characterized by the fact that the windings are so proportioned as to establish equal induction in each traflic rail and the coupler when connected to the source of current and so connected that voltage induced in said windings by current flowing in the same direction in the two rails and the coupler add their effects when connected to the receiving device, a fourth winding on the train adapted to be influenced by space magnetic fields, and means for varying the effectiveness of said fourth winding and combining the voltage induced therein by a space magnetic field with that induced in the first mentioned. three windings by the same field to balance out the effect of said space field on the apparatus.

10. Train signaling apparatus of the type comprising a train-carried inductor adapted to receive influences from the traffic track by electromagnetic induction to operate a receiving device, a second train-carried inductor adapted to be influenced by space magnetic fields, and manually controlled means for varying the efi'ectiveness of said second train-carried inductor and to combine the voltage induced therein by a space magnetic field with that induced in the first mentioned inductor by the same field to balance out the efiect of said space magnetic field on the said receiving device.

In testimony whereof I aflix my signature.

RICHARD P. BALLOU. 

